3 replies to this topic

[NDark]

hi ,


I render a mesh using basic texture mapping , the texture coordinate is correct , however the color of some parts are too strange , like red channel is masked .

the result is like this screen shot:


this is original image for texture



I use VS2005 and OpenGL to render.

the following is image reading and texture generation process :

System::Drawing::Bitmap *TexImage ;

System::Drawing::Rectangle Rec ;

System::Drawing::Imaging::BitmapData *bmdata ;


// read image

TexImage = new System::Drawing::Bitmap( gTexfilename.c_str() ) ;// read image

Rec.X = 0 ;

Rec.Y = 0 ;

Rec.Width = TexImage->Width ;

Rec.Height = TexImage->Height ;


bmdata = new System::Drawing::Imaging::BitmapData ;

TexImage->LockBits( Rec , System::Drawing::Imaging::ImageLockMode::ReadOnly ,

	Imaging::PixelFormat::Format24bppRgb , bmdata ) ;



// generation texture

glGenTextures( 1 , &tid ) ;

glBindTexture( GL_TEXTURE_2D , tid ) ;


glTexParameteri( GL_TEXTURE_2D , GL_TEXTURE_MAG_FILTER , GL_LINEAR ) ;

glTexParameteri( GL_TEXTURE_2D , GL_TEXTURE_MIN_FILTER , GL_LINEAR ) ;

glTexEnvi( GL_TEXTURE_ENV , GL_TEXTURE_ENV_MODE , GL_REPLACE ) ;


glTexImage2D( GL_TEXTURE_2D , 0 , GL_RGB8 , 

		TexImage->Width , TexImage->Height , 

		0 , GL_RGB , GL_UNSIGNED_BYTE , 

		(void*) bmdata->Scan0 ) ;

and render process is following :

glBindTexture( GL_TEXTURE_2D , gTexid ) ; // bind texture itri

glEnable( GL_TEXTURE_2D ) ;

glDisable( GL_LIGHTING ) ;

glDisable( GL_BLEND ) ;

glColorMask( 1.0 , 1.0 , 1.0 , 1.0 ) ;


glBegin( GL_TRIANGLES ) ;

// do vertex and texture draw

glEnd() ;

glDisable( GL_TEXTURE_2D ) ;

Does anyone know where is the key process I go wrong ? Thanks in advance .



NDark

[Sol_HSA]

You need to swap the red and blue colors in the texture.

[Kenneth Gorking]

Or when uploading it, using GL_BGR_EXT

[NDark]

Kenneth Gorking said:

Or when uploading it, using GL_BGR_EXT

thank you a lot . It works .
this is correct result.